To ensure that all debt can be paid back with interest the money supply must continually grow - FALLACY! See this simple google spreadsheet - http://bit.ly/f2yE4D

Intrinsic value - FALLACY! Behold, the Subjective Theory of Value - http://en.wikipedia.org/wiki/Subjective_theory_of_value

Concerned about long-term viability of bitcoins? Maybe your concern should be with learning logic and economics first.